How safe is it getting a rental car at SFO and driving to and from Monterey?

I have some United credits expiring and also need to make a stay at an Intercontinental. I am thinking of either visiting Monterey or San Diego since both have Intercontinental hotels.

I am more gravitating towards Monterey, but some friends have told me in the past that people get mugged or robbed just walking outside of SFO terminals???

I don’t know if San Diego is any safer?